The purpose of this study is to examine carefully the mechanical properties of the lung in Bullous Emphysema (B.E.) pre- and post- bullectomy to 1) Establish clearly the mechanism for improvement in airway conductance found in our preliminary study. 2) To examine the factors which are associated with the failure of some patients to maintain this improvement by carefully following a group of patients over a prolonged period with frequent measurements of pulmonary mechanics. 3) Develop from these studies criteria for the selection of patients who will have long-term benefit from bullectomy. Since medical therapy has had a limited overall effectiveness in emphysema, surgical resection of bullae in bullous emphysema has been proposed as a means of decreasing airway resistance (RA) or increasing airway conductance (CA equals 1/RA). No systematic measurement of CA pre- and post-bullectomy had been made prior to our preliminary study. We found that all seven patients who underwent bullectomy increased their airway conductance. In three of these seven patients the improvement diminished over a period of months. Since the dramatic improvement in the other four patients persisted, it is important to establish why some patients only transiently benefit from bullectomy while others experience prolonged improvement. It is our present plan to study a larger group of patients and to follow them over a three year period to accomplish the stated goals of the proposal.